Thermostatic furnace-damper control



April 16, 1929.

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E. VERSTRAETE THERMOSTATIC FURNACE DAMPER CONTROL Filed July I,

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BY 2 ATTORNEY I April 16, 1929. VERSTRAETE 1,708,980

THERMOSTATIC FURNACE DAMPER CONTROL 7 Filed July 1927 2 Sheets-Sheet 2 llllllll lllmml l mm- I N VEN TOR. ZZmanoZ %ns'ra efie BY 44k ATTORNEY Patented Apr, 16, 1929.

UNITED STATES EDMOND VEBS'IRAETE, OF NUTLEI, NEW JERSEY.

TEERMOSTATIC FURfiACE-DAMPEB CONTROL.

Application filed July 1,

This invention relates to automatic damper control mechanism for heating furnaces; and this application is a continuation in part of an application for United States Letters Patent filed by me on or about May 29, l925,and identified by Serial Number 33,656.

This invention has for its principal object to provide a novel and simply constructed thermostatically controlled ,electro mechanical means for automatically actuating the draft dampers of heating furnaces whereb the temperature in artificially heated bnil ings may be in turn automatically regulated.

Other objects of this invention, not at this time more particularly enumerated, will be clearly understood from the following detailed description of the same. I

The invention is clearly illustrated in the accompanying drawings, in which Figure 1 is a diagrammatic view illustrating the operation of the, a paratus when functioning to open the dra ts of a heating furnace; and Figure 2 is a similarview illustrating the operation of the apparatus when functioning to close the drafts of the heating apparatus.

Figure 3 is a side \view in elevation of the 'elcctro-mechanical furnace draft actuating means, with the casin thereof open to disclose the interior medhanism thereof; Figure 4 is a vertical sectional view ofthe same, taken on line H in Figure 3; and Figure 5 is a fragmentary detail view of an electric circuit control switch which 'forms a novel and essential part of the electro-mechanical furnace draft actuating means.

Similar characters of reference are employed in all of the hereinabove described views, to indicate corresponding parts.

Referring now to said drawings, the reference character 6 indicates a casing in which the electro-mechanical furnace draft actuating mechanism is enclosed, and which may be suitably mounted or supported in the vicinity of the furnace to be served thereby. The front wall 7 of the casing 6 may be made in the form of a removable part orcover-plate. The rear wall 8 of the casing 6 and said front wall or cover plate 7 thereof are respectively provided with hearing portions 9 and 10 in ali out one with the other. J ournaled in an extending through and between said bearing portions 9 and 10 is a driven shaft 11.

1927. Serial No. 202,794n

Fixed on the exteriorly projecting forward end of said shaft 11 is a crank-arm 12; and, n like manner, fixed on the exteriorly proectmg rearward end of said shaft 11 is a second crank-arm 13. Said crank-arms 12 and 13 extend in op osite directions, so that when one is up the ot er is down and vice versa.

Secured within and to the. top wall 14 of the casing 6 is an electric motor 15, which when served with electric current is adapted to drive the shaft 11 through suitable intermediate transmission mechanism; Such transmission mechanism referably comprises a drive-pinion 16 fixed on the armature shaft 16 of said motor 15, which inion 16 meshes with and drives a-gear 17 xed on a transmission shaft 18. The sidewalls of said casing 6 are respectively provided with hearing members 19 and. 20 in transverse ali ment one with the other. Said transmission shaft 18 is journaled in and extends between said bearing members 19 and 20. Secured upon said. transmission shaft 18 is a drive worm 21 which meshes with and drives a worm gear 22 which is fixed on said main shaft 11 and whereby the latter is rotated.

Supported by posts 23 extending forward-; 1y into the casing interior from the rear walla I 8 thereof, is a carrier bar or plate 24' of insu-- lation material upon which is supported a mechanically actuated electric switch mechanism for inclusion in the thermostatic-eontrol circuit of the apparatus. Fixed on said carrier bar or late 24 intermediateits' ends is. a metallic circuit connection 25 provided with a binding screw 26 or other suitable .means for connectin a circuit wire therewith."" 'The lower on of said circuit connection 25 is furnished with a fulcrum pin 27 upon which is pivotally mountedan oscillatable switch member having' oppositelyj extending 'switch ar msf 28; a1'id/29. Secured on saidcarrijefir barbr plate'24, adjacent toone end thereofds a 'contact clip 30 engageable at propertimesiby the switcharin 28 of said oscillatable switch member, said contact clip 30 being provided witha binding screw 31 .or other suitablemeans for connecting a circuit wire therewith; and, in like manner, secured on saidcarrier bar or plate 24, adjacent to its opposite end, is a contact ch 32 em gageable at P113161" times b 29 of said osci stable swi ch member, said the switch arm contact clip 32 being likewise provided with a binding screw 33 or other suitable means for connecting acircuit wire therewith.

A suitably insulated terminal binding post 34: is provided in connection with the casing wall in desired location to receive connection at its exterior end oat an electrical conductor 35 leading fromv any suitable source of electric energy. One pole of the motor is connected with theinterior end of said binding post 34 by tin-electrical conductor 36. The other pole of said motor is connected with the inner end of a similar terminal binding post 3 L by an el ctrical conductor 36, and from the outer end of said binding post 34: leads the return circuit wire 37. lincluded in the motor circuit thus'provided is a normally open switch forming part of a relay mechanism to be presently described.

Another suitably insulated binding post 34s is provided in connection with the cas-' ing wall in desired location to receive con nection at its exterior end of a shunt branch conductor 35 leading -from the current deliveryside of said motor circuit. Included in said branch conductor 35 is a voltage reducing coil or resistance R, or, if desired a transformer or other suitable electrical means for stepping down the voltage in a thermostatic control circuit in shunt with said motor circuit and operating, as will be pre ently made clear, to open and close the latter at proper times. The inner end of said binding" post 34 is connected with said circuit connection of said mechanically actuated switch mechanism by an electrical couductor 25'. A pair of suitably insulated. terminal binding posts 38 and 89 are also pro- .vided in connection with the casing wall in desired location; the contact clip being connected with the interior end of the binding post 38 by an electrical conductor 40, while the contact clip 52 is connected with the interior end of the other binding post 39 by an electrical conductor ll. mostati'c switch means is suitably located so as to be subject to temperature variations within the building heated by the :t'urnace served by the electro-mechanical draft actuating mechanism. Said thermostatic primary switch means may be of any desired specific form and construction comprising a thermostatic switch arm 42 subject to deflection under temperature variations, and pair of fixed contacts i3 and fit selectively engageable by said thermostatic switch arm 12.

One fixed contact, as 48, is connected in cir cuit with said contact clip 30 by an electrical. conductor 45 leading thereto from the binding post 38; and the other fixed contact,

as M, is connected in circuit with said co:n-'

tact clip 32 by an electrical conductor 46 lead ing thereto from the binding post 39. The thermostatic switch arm is connected by a circuit wire or conductor 47 with one pole A thermoaeso of a magnet M forming part of the relay controlling the opening and closing of the main motor circuit, the other pole of said magnet M being connected to the return wire 37 of said motor circuit.

Cooperating with said magnet M as its armature is a pivoted switch arm A, normally retained in open position by a spring S. The return wire 37 of the motor circuit is con nected with said switch arm A, and the continuation of said return wire 37 is connected with a stationary contact C with which said switch arm A is engaged when moved by the energizing of the magnet M, thus closing the main circuit serving the motor 15.

The reference character 18 indicates an oscillatable trip-lever which is pivoted by its lower end on a fulcrum stud or screw d9 lined in a boss 50 within the lower end of said casing 6. Said trip-lever 48 is provided intermediate its ends with a yolre-irame 51 which straddles said main shaft ll, and fixed on the latter so as to be rotated thereby is a cam-member 52. Said cam-member 52, when rotated, engages the sides of said yoke-frame .1

51 and causes said trip-lever 4:8 to swing or oscillate on its fulcrum. The free end of said trip-lever 48 is provided with a socket member 53 in which is housed a compression or thrust spring 54 which yielda'bly thrusts against the inner end of a nose-piece 55 which projects outwardly frbm said socket-,member 53 and is slidable therein. Said nose-piece 55 is provided in its body with an elongated slot 5'6 through which extends a stopin 53 fixed crosswise within said socket-mere or 53,

thus serving to limit the outward movement of said nose-piece whereby the same is retained in operative assembled relation to said socket-member 53.

The reference character 58 indicates a heating furnace to be served by the draft actuating mechanism. Said furnace is provided with any suitable form of ash-pit or bottom air admission damper means pivoted for opening and closing movement, and with a pivoted smolrepipe damper means 69 of any,

suitable term. The crank-arm 12 of the damper actuating mechanism is connected with said bottom damper 59 through a suitable connection such as a flexible wire, cord, chain or the like 61, which may be guided for operative movement by suitably located pulley or pulleys 82; and in like manner the eranlearm 13 ot the damper actuating mechanism is connected with said smoke-pipe damper 50 through a suitable connection such-as a flexible wire, cord, chain or the like (53, which also may be guided for operative movement by suitably located pulley or pulleys =64. r

In the operation of'the damper actuating mechanism, the thermostatic control circuit of the apparatus governs the properly timed opening and closing of the motor service circuit, the mechanically actuated switch mechanism servin to break the thermostatic control circuit a ter a given actuation of the furnace dampers to thereby in turn cause the interruption of the motor circuit through the release of the relay switch, and at the same time alternately bringing into the control ciromit the respective fixed contacts of the thermostatic switch means. By the arrangement of main motor service circuit, and shunt thermostatic control circuit including a voltage reducing means, the'device may be easily connected with 110 or 220 volt power lines, where by adequate current for motor operationis assured, while a reduced or low voltage current is supplied through the thermostatic switch to protect its delicate contacts against injury. This electrical mode of connection is not per so new with me, the new feature of my arrangement being the provision of the novel mechanically actuated switch mechanism in the thermostatic control circuit, the construction and arrangement of which is such that not only a very quick break is attained, but the relation of this switch mech, anism to the damper actuating elements is such that accurate control, and operation of the latter is secured without risk of either overthrow or partially completed movements of the same.

Assume that the thermostatic switch arm 42 deflects to the left to engage the contact 44 under falling room temperature conditions, and deflects to the right to engage the contact 43 under rising room temperature conditions. When the parts of the elect-ro-mechanical damper actuating mechanism are disposed in the position shown inFigure 3 the air admission damper 59 is open and the smoke-pipe damper is closed, under these circumstances the switch arm 28 being engaged with the con-- tact clip so that the thermostat contact 43 is operatively connected in the thermostatic control circuit. Under these conditions the furnace is active. Asthe heat provided by the furnace operation causes room temperature to rise, the effect of said rising temperature is to deflect the thermostatic switch arm 42 toward the contact 43, and when the engagement of the latter by the former occurs the motor circuit will be completed. The electric current being then delivered by the conductors and 35 through the resistance R, conductor 25', circuit connection 25, mechanical switch arm 28, contact clip 30. thernrostatic contact 43. thermostatic switch :nm 42. conductor47, to the magnet M and thence back to the source of energy through the conductor. 37. The thermostatic control switch being thus closed the magnet M is energized and pulls toward it the switch arm A sons to bring the same into engagement with the contact C. In this manner the service circuit throu h the motor is closed and the motor is caused to operate. The operation of the mo-- tor drives the shaft 11 through the intermediate transmission mechanism. The rotation of said shaft 11 turns the crank-arm 12-down and the crank-arm 13-up, thereby relaxing the connection 61 to permit the damper 59 to close, and drawing up the connection 63 to open the damper 60, whereby the furnace is checked. As the shaft 11 rotates to operate the crank-arms 12 and 13 in the manner and for the purposes above described, the cammember 52 is also rotated in engagement with the yoke-frame 51 whereby the trip-lever 48 is caused to swing from right to left. In thus moving, the trip-lever carries the nose-picce away from the upwardly swung switcharm 28 and causesthe same to pass the pivotal point of the mechanically actuated switch means and thence into engagement with the downwardly swung switch arm 29, the nose-piece yielding inwardly against the compression of the spring 54 during'such movement, so that upon passing intoengagement with said downwardly swung switch arm the outward thrust of the spring presses the nose-piece sharply upward, and thus swings upward the switch-arm 29 into engagement with the contact clip 32, while at the same time swinging downward the switch-arm 28 out of engagement with the contact clip 30 with a quick circuit breaking movement. The thermostatic control circuit is thus immediately interrupted whereby the magnet M is deenergized and in turn the motor service circuit is interrupted by the movement of the switch arm'A away from the contacts C under the influence of the spring S. It will be obvious that the interruption of current to the motor stops the power transmission to the shaft 11, the arrangement of the. means for actuating the mechanical switch being such that rotation of the shaft 11 is effectively stopped upon completion of a half revolution thereof, such half revolution being sufficient to turn the crank-arms 12 and 13 in the manner and for the purposes above stated. The operations of the mechanically actuated switch, as thus brought about, further serves to alter the thermostatic control circuit, so that as the thermostat cont-act 43 is cut out of such circuit the opposite thermostat contact 44 is brought into thecircuit by the engagement of the switch-arm 29 with the contact clip 32, thus automatically preparing the thermostatic switch for operation under falling temperature conditions. \Vhen,

therefore, under checked condition of the furnace, room tem erature falls to that degree sufiicient to de ect the thermostatic switch arm 42 to the left and into engagement with the thermostat contact 44, the motor circuit will-again be closed through the operation of the relay switch, and the motor 15 put in motion, power being thereupon again transmitted to the shaft 11, whereby the crank-arm 12 will be turned up and the crank-arm 13 drawn down to open the damper 59, and to relax the connection 63 to close the damper 60, so that normal combustidn of fuel within the furnace with consequent delivery of heat is resumed. Upon completion of the half turn of the shaft ll'whereby consummation of this oporation is attained, the cam 52 during its roperatures.

tation will again actuate the trip-lever 48 "to move the nose-piece out of engagement with the switch-arm 29 and into engagement with the switch-arm 28, thus oscillating the mechanically operated switch to break the thermostatic control circuit at the contact clip 32 while at the same time resetting such circuit through contact clip 30 to bring the thermostatcontactflfi again into active con trol circuit relation ready to close the same when the thermostatic switch-arm 42 is moved into engagement therewithunder-ms ing temperature conditions. It will be evident that the thermostatic switch may be of the kind that can be set or regulated to make circuit closing contact at desired predetermined maximunnland minimum room tem- While I have herein shown and described my novel electro-mechanical damper actuating means in one preferred form and by way of example, it will be obvious that many changes,.modifications and adaptations may he made therein and in its mode of application to a furnace which will nevertheless be comprised within the spirit of my invention; consequently I do not limit myself to the exact arrangements and combinations of parts hereinabove described, nor do I confine myself to the exact details of the construction of said parts as shown in the accompanying" drawings.

Having thus described my nvention, It claim 1. An electro-mechanical damper actuating mechanism, comprising a shaft provided with damper actuating, means; an electric motor for driving said 'shaftya circuit for said motor including a relay actuated switch; a thermostatic control circuit for operating said relay actuated switch, comprisin a thermostatic switch arm and a pair of fixed thermostat contacts selectively engageable by said arm when influenced by rising andfalling temperature, a control circuit interrupter comprising an oscillate-able switch means and a. pair of stationarycontacts selectively engugeable thereby. said stationary contacts of said interrupt-er being respectively connected in series with the respective fixed thermostat contacts; a pivoted trip lever having a yieldable nosing to engage and'operate saidoscillatable switch means of said interrupter; and

said shaft having a cam for actuating said tory switch member having oppositely extending' arms pivoted intermediate said contact clips and so arranged that when one arm is in contact with one contact clip the other arm is out of contact with the other contact clip, means for electrically connecting togethercontact clips of said cut-out switch with correspending fixed contacts of said thermostat; a

pivoted trip lever having a yieldable' spring pressed nosing to engage and operate said oscillatory switch member; and means driven by said shaft "for operating said trip lever upon'completion of a damper actuating operation to thereby interrupt the control circuit closed through one interconnected contact clip and fixed thermostat contact and at the same time set said control circuit for closing through the other interconnected contact clip and fixed, thermostat contact.

3. An electro mechanical damper actuating mechanism, comprising a shaft provided with damper actuating means; an electric motor for driving said; shaft; a'c'ircuit for said motor including a relay actuated switch, a thermostatic control circuit for operating said relay actuated switch, comprising a thermostat having a pair of spaced apart fined contacts and a thermostatic switch arm intermediate said fixed contacts, a cut-out switch having a pair of spaced apart contact clips, an osclllatory switch member having oppositely extendin arms pivoted intermediate said contact c ipsand so arranged that when one arm is in contact with one contact clip the other arm isout of contact with the other contact clip, means for. electrically connecting to .gether contact clips of said cutout switch with corresponding fixed "contacts of said thermostat; a pivoted trip lever having a .yieldable springpressed nosing to engage and operate said oscillatory switch member; a

yokedrame connected with said trip-lever; and a cam on said shaft cooperating with said yoke-frame to actuate said trip-lever.

In testimony, that I claim the invention set forth above I have hereunto'sct hand this 27 day of June, 1927.

EDMOND VERSTERAETE. 

